Hi Jason,
Thank you for reply.
On Wed, Nov 5, 2025 at 9:59 AM Jason Wang <[email protected]> wrote:
>
> On Wed, Nov 5, 2025 at 4:49 PM Jinpu Wang <[email protected]> wrote:
> >
> > Hello QEMU developers,
> >
> > I’m encountering a migration failure when trying to live-migrate a VM
> > from a newer host (kernel 6.12 + QEMU 9.2.4) to an older one (kernel
> > 6.1 + QEMU 8.2.10).
> > Migration in the forward direction (old → new) works fine, but after
> > rebooting the guest on the new host, migration back to the old host
> > fails.
> >
> > ________________________________
> >
> > Issue summary
> >
> > Source host: kernel 6.12, QEMU 9.2.4
> >
> > Destination host: kernel 6.1, QEMU 8.2.10
> >
> > VM type: pc-q35-8.2, using virtio-net-pci with vhost backend
> >
> > Symptom: Migration from 9.2.4 → 8.2.10 fails with virtio-net load error.
> >
> > Error log (destination):
> >
> > 2025-09-23T07:06:14.915708Z qemu-8.2: Features 0x1c0010130afffa7
> > unsupported. Allowed features: 0x179bfffe7
> > 2025-09-23T07:06:14.915843Z qemu-8.2: Failed to load virtio-net:virtio
> > 2025-09-23T07:06:14.915851Z qemu-8.2: error while loading state for
> > instance 0x0 of device '0000:00:02.0:06.0/virtio-net'
> > 2025-09-23T07:06:14.917894Z qemu-8.2: load of migration failed:
> > Operation not permitted
> >
> > ________________________________
> >
> > Analysis
> >
> > It appears that virtio-net feature bits differ between the two versions.
> > On QEMU 9.2.4, virtio-net reports additional features:
> >
> > VIRTIO_F_RING_RESET
> >
> > VIRTIO_NET_F_HOST_USO
> >
> > VIRTIO_NET_F_GUEST_USO4
> >
> > VIRTIO_NET_F_GUEST_USO6
> >
> > These are not present (or not supported) on QEMU 8.2.10, which causes
> > the migration state load to fail.
>
> Interesting, we've already done the compat work:
>
> GlobalProperty hw_compat_8_1[] = {
> { TYPE_PCI_BRIDGE, "x-pci-express-writeable-slt-bug", "true" },
> { "ramfb", "x-migrate", "off" },
> { "vfio-pci-nohotplug", "x-ramfb-migrate", "off" },
> { "igb", "x-pcie-flr-init", "off" },
> { TYPE_VIRTIO_NET, "host_uso", "off"},
> { TYPE_VIRTIO_NET, "guest_uso4", "off"},
> { TYPE_VIRTIO_NET, "guest_uso6", "off"},
> };
> const size_t hw_compat_8_1_len = G_N_ELEMENTS(hw_compat_8_1);
Yeah, I noticed the same.
>
> >
> > The issue seems related to the introduction of these features and how
> > they are handled during incoming migration when the target QEMU does
> > not recognize them.
> >
> > ________________________________
> >
> > Reproduction steps
> >
> > Start VM on host with QEMU 8.2.10 (kernel 6.1).
> >
> > Migrate to host with QEMU 9.2.4 (kernel 6.12).
> > → Migration succeeds.
> >
> > Reboot the guest on the 9.2.4 host.
> >
> > Attempt to migrate back to QEMU 8.2.10 host.
> > → Migration fails with virtio-net load error (see log above).
> >
> > ________________________________
> >
> > Expected behavior
> >
> > Migration from newer QEMU to older version should either:
> >
> > gracefully ignore unsupported virtio-net features, or
> >
> > fail with a clear compatibility message before starting migration.
> >
> > Currently, migration starts and fails during device state load.
> >
> > ________________________________
> >
> > Related patch
> >
> > I found this commit that looks relevant but is already included in
> > both 8.2.10 and 9.2.4:
> >
> > https://lore.kernel.org/qemu-devel/[email protected]/
> >
> > ________________________________
> >
> > VM configuration
> >
> > -uuid dbaf0b1f-4dc5-4462-86b1-d82107b58599
> > -name Serverwittchendbaf0b1f-4dc5-4462-86b1-d82107b58599
> > -M pc-q35-8.2
>
> Could you double check if this is used in both source and destination?
>
> > -accel kvm,kernel-irqchip=split
> > -cpu SierraForest-v2
> > -smp 7,sockets=128,cores=1,maxcpus=128,threads=1
> > -m 4096,slots=252,maxmem=256G
> > -bios /usr/share/ovmf/OVMF.fd
> > -device
> > virtio-net-pci,netdev=hostnet6,id=net6,mac=02:01:17:9b:9a:35,bus=pci.0,addr=0x6
> > -netdev tap,ifname=n0201179b9a35,id=hostnet6,script=no,downscript=no
> >
> > ________________________________
> >
> > Question
> >
> > Is this expected behavior (i.e. migration incompatibility due to newer
> > virtio-net feature bits)?
>
> No.
>
> Could you check if
>
> 1) those features were enabled or not via "info qtree" when using pc-q35-8.2.
here is output on the machine with 9.2.4, all uso features are enabled:
[email protected]:~$ nc -U
/opt/profitbricks/vcb/pbkvm/mon/791776d3-72cc-4392-8603-bb5bdc537011.sock
{"QMP": {"version": {"qemu": {"micro": 4, "minor": 2, "major": 9},
"package": ""}, "capabilities": ["oob"]}}
{'execute':'qmp_capabilities'}
{"return": {}}
{'execute':'human-monitor-command','arguments':{'command-line':'info virtio'}}
{"return": "/machine/peripheral-anon/device[1]/virtio-backend
[virtio-rng]\r\n/machine/peripheral/virtio-disk5/virtio-backend
[virtio-blk]\r\n/machine/peripheral/virtio-disk7/virtio-backend
[virtio-blk]\r\n/machine/peripheral/net6/virtio-backend
[virtio-net]\r\n"}
{'execute':'human-monitor-command','arguments':{'command-line':'info qtree'}
}
{"return": "bus: main-system-bus\r\n type System\r\n dev: ps2-mouse,
id \"\"\r\n gpio-out \"\" 1\r\n dev: ps2-kbd, id \"\"\r\n
gpio-out \"\" 1\r\n dev: hpet, id \"\"\r\n gpio-in \"\" 2\r\n
gpio-out \"\" 1\r\n gpio-out \"sysbus-irq\" 32\r\n timers = 3
(0x3)\r\n msi = false\r\n hpet-intcap = 16711940 (0xff0104)\r\n
hpet-offset-saved = true\r\n mmio
00000000fed00000/0000000000000400\r\n dev: ioapic, id \"\"\r\n
gpio-in \"\" 24\r\n version = 32 (0x20)\r\n mmio
00000000fec00000/0000000000001000\r\n dev: q35-pcihost, id \"\"\r\n
MCFG = 3758096384 (0xe0000000)\r\n pci-hole64-size = 34359738368
(32 GiB)\r\n below-4g-mem-size = 2147483648 (2 GiB)\r\n
above-4g-mem-size = 2147483648 (2 GiB)\r\n smm-ranges = true\r\n
x-pci-hole64-fix = true\r\n x-config-reg-migration-enabled =
true\r\n bypass-iommu = false\r\n bus: pcie.0\r\n type
PCIE\r\n dev: pcie-root-port, id \"rp.2\"\r\n
x-migrate-msix = true\r\n bus-reserve = 4294967295
(0xffffffff)\r\n io-reserve = 18446744073709551615 (16 EiB)\r\n
mem-reserve = 18446744073709551615 (16 EiB)\r\n
pref32-reserve = 18446744073709551615 (16 EiB)\r\n
pref64-reserve = 18446744073709551615 (16 EiB)\r\n x-speed =
\"16\"\r\n x-width = \"32\"\r\n power_controller_present
= true\r\n disable-acs = false\r\n chassis = 0 (0x0)\r\n
slot = 1 (0x1)\r\n hotplug = true\r\n
x-do-not-expose-native-hotplug-cap = false\r\n port = 0
(0x0)\r\n aer_log_max = 8 (0x8)\r\n
x-pci-express-writeable-slt-bug = false\r\n addr = 04.0\r\n
romfile = \"\"\r\n romsize = 4294967295 (0xffffffff)\r\n
rombar = 1 (0x1)\r\n multifunction = false\r\n
x-pcie-lnksta-dllla = true\r\n x-pcie-extcap-init = true\r\n
failover_pair_id = \"\"\r\n acpi-index = 0 (0x0)\r\n
x-pcie-err-unc-mask = true\r\n x-pcie-ari-nextfn-1 = false\r\n
x-max-bounce-buffer-size = 4096 (4 KiB)\r\n
x-pcie-ext-tag = false\r\n busnr = 0 (0x0)\r\n class PCI
bridge, addr 00:04.0, pci id 1b36:000c (sub 0080:0000)\r\n bar
0: mem at 0x88644000 [0x88644fff]\r\n bus: rp.2\r\n
type PCIE\r\n dev: pcie-root-port, id \"rp.1\"\r\n
x-migrate-msix = true\r\n bus-reserve = 4294967295
(0xffffffff)\r\n io-reserve = 18446744073709551615 (16 EiB)\r\n
mem-reserve = 18446744073709551615 (16 EiB)\r\n
pref32-reserve = 18446744073709551615 (16 EiB)\r\n
pref64-reserve = 18446744073709551615 (16 EiB)\r\n x-speed =
\"16\"\r\n x-width = \"32\"\r\n power_controller_present
= true\r\n disable-acs = false\r\n chassis = 0 (0x0)\r\n
slot = 0 (0x0)\r\n hotplug = true\r\n
x-do-not-expose-native-hotplug-cap = false\r\n port = 0
(0x0)\r\n aer_log_max = 8 (0x8)\r\n
x-pci-express-writeable-slt-bug = false\r\n addr = 03.0\r\n
romfile = \"\"\r\n romsize = 4294967295 (0xffffffff)\r\n
rombar = 1 (0x1)\r\n multifunction = false\r\n
x-pcie-lnksta-dllla = true\r\n x-pcie-extcap-init = true\r\n
failover_pair_id = \"\"\r\n acpi-index = 0 (0x0)\r\n
x-pcie-err-unc-mask = true\r\n x-pcie-ari-nextfn-1 = false\r\n
x-max-bounce-buffer-size = 4096 (4 KiB)\r\n
x-pcie-ext-tag = false\r\n busnr = 0 (0x0)\r\n class PCI
bridge, addr 00:03.0, pci id 1b36:000c (sub 0080:0000)\r\n bar
0: mem at 0x88645000 [0x88645fff]\r\n bus: rp.1\r\n
type PCIE\r\n dev: pcie-pci-bridge, id \"pci.0\"\r\n msi =
\"auto\"\r\n x-pci-express-writeable-slt-bug = false\r\n
addr = 02.0\r\n romfile = \"\"\r\n romsize = 4294967295
(0xffffffff)\r\n rombar = 1 (0x1)\r\n multifunction =
false\r\n x-pcie-lnksta-dllla = true\r\n
x-pcie-extcap-init = true\r\n failover_pair_id = \"\"\r\n
acpi-index = 0 (0x0)\r\n x-pcie-err-unc-mask = true\r\n
x-pcie-ari-nextfn-1 = false\r\n x-max-bounce-buffer-size = 4096
(4 KiB)\r\n x-pcie-ext-tag = false\r\n busnr = 0
(0x0)\r\n class PCI bridge, addr 00:02.0, pci id 1b36:000e (sub
0080:0000)\r\n bar 0: mem at 0x8000100000 [0x80001000ff]\r\n
bus: pci.0\r\n type PCI\r\n dev: virtio-blk-pci,
id \"virtio-disk7\"\r\n disable-legacy = \"off\"\r\n
disable-modern = false\r\n class = 0 (0x0)\r\n
ioeventfd = true\r\n vectors = 3 (0x3)\r\n
virtio-pci-bus-master-bug-migration = false\r\n
migrate-extra = true\r\n modern-pio-notify = false\r\n
x-disable-pcie = false\r\n page-per-vq = false\r\n
x-ignore-backend-features = false\r\n ats =
false\r\n x-ats-page-aligned = true\r\n
x-pcie-deverr-init = true\r\n x-pcie-lnkctl-init = true\r\n
x-pcie-pm-init = true\r\n
x-pcie-pm-no-soft-reset = false\r\n x-pcie-flr-init =
true\r\n aer = false\r\n addr = 07.0\r\n
romfile = \"\"\r\n romsize = 4294967295 (0xffffffff)\r\n
rombar = 1 (0x1)\r\n multifunction = false\r\n
x-pcie-lnksta-dllla = true\r\n x-pcie-extcap-init
= true\r\n failover_pair_id = \"\"\r\n
acpi-index = 0 (0x0)\r\n x-pcie-err-unc-mask = true\r\n
x-pcie-ari-nextfn-1 = false\r\n
x-max-bounce-buffer-size = 4096 (4 KiB)\r\n x-pcie-ext-tag
= false\r\n busnr = 1 (0x1)\r\n class SCSI
controller, addr 01:07.0, pci id 1af4:1001 (sub 1af4:0002)\r\n
bar 0: i/o at 0x6000 [0x607f]\r\n bar 1: mem at
0x88400000 [0x88400fff]\r\n bar 4: mem at 0x8000000000
[0x8000003fff]\r\n bus: virtio-bus\r\n type
virtio-pci-bus\r\n dev: virtio-blk-device, id \"\"\r\n
drive = \"drive-virtio-disk7\"\r\n
backend_defaults = \"auto\"\r\n logical_block_size =
512 (512 B)\r\n physical_block_size = 512 (512 B)\r\n
min_io_size = 0 (0 B)\r\n opt_io_size = 0
(0 B)\r\n discard_granularity = 4294967295 (4 GiB)\r\n
write-cache = \"auto\"\r\n share-rw =
false\r\n account-invalid = \"auto\"\r\n
account-failed = \"auto\"\r\n rerror = \"auto\"\r\n
werror = \"auto\"\r\n cyls = 16383
(0x3fff)\r\n heads = 16 (0x10)\r\n secs
= 63 (0x3f)\r\n lcyls = 0 (0x0)\r\n
lheads = 0 (0x0)\r\n lsecs = 0 (0x0)\r\n
serial = \"b663a1b71b486d62\"\r\n config-wce = true\r\n
request-merging = true\r\n num-queues =
2 (0x2)\r\n queue-size = 256 (0x100)\r\n
seg-max-adjust = true\r\n iothread-vq-mapping =
<null>\r\n discard = false\r\n
report-discard-granularity = true\r\n write-zeroes =
true\r\n max-discard-sectors = 4194303 (0x3fffff)\r\n
max-write-zeroes-sectors = 4194303 (0x3fffff)\r\n
x-enable-wce-if-config-wce = true\r\n
indirect_desc = true\r\n event_idx = true\r\n
notify_on_empty = true\r\n any_layout = true\r\n
iommu_platform = false\r\n packed =
false\r\n queue_reset = true\r\n
in_order = false\r\n use-started = true\r\n
use-disabled-flag = true\r\n x-disable-legacy-check
= false\r\n dev: virtio-blk-pci, id \"virtio-disk5\"\r\n
disable-legacy = \"off\"\r\n disable-modern =
false\r\n class = 0 (0x0)\r\n ioeventfd =
true\r\n vectors = 3 (0x3)\r\n
virtio-pci-bus-master-bug-migration = false\r\n
migrate-extra = true\r\n modern-pio-notify = false\r\n
x-disable-pcie = false\r\n page-per-vq = false\r\n
x-ignore-backend-features = false\r\n ats =
false\r\n x-ats-page-aligned = true\r\n
x-pcie-deverr-init = true\r\n x-pcie-lnkctl-init = true\r\n
x-pcie-pm-init = true\r\n
x-pcie-pm-no-soft-reset = false\r\n x-pcie-flr-init =
true\r\n aer = false\r\n addr = 05.0\r\n
romfile = \"\"\r\n romsize = 4294967295 (0xffffffff)\r\n
rombar = 1 (0x1)\r\n multifunction = false\r\n
x-pcie-lnksta-dllla = true\r\n x-pcie-extcap-init
= true\r\n failover_pair_id = \"\"\r\n
acpi-index = 0 (0x0)\r\n x-pcie-err-unc-mask = true\r\n
x-pcie-ari-nextfn-1 = false\r\n
x-max-bounce-buffer-size = 4096 (4 KiB)\r\n x-pcie-ext-tag
= false\r\n busnr = 1 (0x1)\r\n class SCSI
controller, addr 01:05.0, pci id 1af4:1001 (sub 1af4:0002)\r\n
bar 0: i/o at 0x6080 [0x60ff]\r\n bar 1: mem at
0x88402000 [0x88402fff]\r\n bar 4: mem at 0x8000008000
[0x800000bfff]\r\n bus: virtio-bus\r\n type
virtio-pci-bus\r\n dev: virtio-blk-device, id \"\"\r\n
drive = \"drive-virtio-disk5\"\r\n
backend_defaults = \"auto\"\r\n logical_block_size =
512 (512 B)\r\n physical_block_size = 512 (512 B)\r\n
min_io_size = 0 (0 B)\r\n opt_io_size = 0
(0 B)\r\n discard_granularity = 4294967295 (4 GiB)\r\n
write-cache = \"auto\"\r\n share-rw =
false\r\n account-invalid = \"auto\"\r\n
account-failed = \"auto\"\r\n rerror = \"auto\"\r\n
werror = \"auto\"\r\n cyls = 16383
(0x3fff)\r\n heads = 16 (0x10)\r\n secs
= 63 (0x3f)\r\n lcyls = 0 (0x0)\r\n
lheads = 0 (0x0)\r\n lsecs = 0 (0x0)\r\n
serial = \"2ea4900a095b1012\"\r\n config-wce = true\r\n
request-merging = true\r\n num-queues =
2 (0x2)\r\n queue-size = 256 (0x100)\r\n
seg-max-adjust = true\r\n iothread-vq-mapping =
<null>\r\n discard = false\r\n
report-discard-granularity = true\r\n write-zeroes =
true\r\n max-discard-sectors = 4194303 (0x3fffff)\r\n
max-write-zeroes-sectors = 4194303 (0x3fffff)\r\n
x-enable-wce-if-config-wce = true\r\n
indirect_desc = true\r\n event_idx = true\r\n
notify_on_empty = true\r\n any_layout = true\r\n
iommu_platform = false\r\n packed =
false\r\n queue_reset = true\r\n
in_order = false\r\n use-started = true\r\n
use-disabled-flag = true\r\n x-disable-legacy-check
= false\r\n dev: virtio-net-pci, id \"net6\"\r\n
disable-legacy = \"off\"\r\n disable-modern = false\r\n
ioeventfd = true\r\n vectors = 4 (0x4)\r\n
virtio-pci-bus-master-bug-migration = false\r\n
migrate-extra = true\r\n modern-pio-notify = false\r\n
x-disable-pcie = false\r\n page-per-vq = false\r\n
x-ignore-backend-features = false\r\n ats =
false\r\n x-ats-page-aligned = true\r\n
x-pcie-deverr-init = true\r\n x-pcie-lnkctl-init = true\r\n
x-pcie-pm-init = true\r\n
x-pcie-pm-no-soft-reset = false\r\n x-pcie-flr-init =
true\r\n aer = false\r\n addr = 06.0\r\n
romfile = \"efi-virtio.rom\"\r\n romsize = 262144
(0x40000)\r\n rombar = 1 (0x1)\r\n multifunction
= false\r\n x-pcie-lnksta-dllla = true\r\n
x-pcie-extcap-init = true\r\n failover_pair_id = \"\"\r\n
acpi-index = 0 (0x0)\r\n x-pcie-err-unc-mask =
true\r\n x-pcie-ari-nextfn-1 = false\r\n
x-max-bounce-buffer-size = 4096 (4 KiB)\r\n x-pcie-ext-tag
= false\r\n busnr = 1 (0x1)\r\n class Ethernet
controller, addr 01:06.0, pci id 1af4:1000 (sub 1af4:0001)\r\n
bar 0: i/o at 0x6100 [0x611f]\r\n bar 1: mem at
0x88401000 [0x88401fff]\r\n bar 4: mem at 0x8000004000
[0x8000007fff]\r\n bar 6: mem at 0xffffffffffffffff
[0x3fffe]\r\n bus: virtio-bus\r\n type
virtio-pci-bus\r\n dev: virtio-net-device, id \"\"\r\n
csum = true\r\n guest_csum = true\r\n
gso = true\r\n guest_tso4 = true\r\n
guest_tso6 = true\r\n guest_ecn = true\r\n
guest_ufo = true\r\n guest_announce = true\r\n
host_tso4 = true\r\n host_tso6 = true\r\n
host_ecn = true\r\n host_ufo = true\r\n
mrg_rxbuf = true\r\n status = true\r\n
ctrl_vq = true\r\n ctrl_rx = true\r\n
ctrl_vlan = true\r\n ctrl_rx_extra = true\r\n
ctrl_mac_addr = true\r\n
ctrl_guest_offloads = true\r\n mq = false\r\n
rss = false\r\n hash = false\r\n
ebpf-rss-fds = <null>\r\n guest_rsc_ext = false\r\n
rsc_interval = 300000 (0x493e0)\r\n mac =
\"02:01:51:df:1b:c5\"\r\n netdev = \"hostnet6\"\r\n
x-txtimer = 150000 (0x249f0)\r\n x-txburst =
256 (0x100)\r\n tx = \"\"\r\n
rx_queue_size = 256 (0x100)\r\n tx_queue_size = 256
(0x100)\r\n host_mtu = 0 (0x0)\r\n
x-mtu-bypass-backend = true\r\n speed = -1
(0xffffffffffffffff)\r\n duplex = \"\"\r\n
failover = false\r\n guest_uso4 = true\r\n
guest_uso6 = true\r\n host_uso = true\r\n
indirect_desc = true\r\n event_idx = true\r\n
notify_on_empty = true\r\n any_layout =
true\r\n iommu_platform = false\r\n
packed = false\r\n queue_reset = true\r\n
in_order = false\r\n use-started = true\r\n
use-disabled-flag = true\r\n x-disable-legacy-check
= false\r\n dev: virtio-rng-pci, id \"\"\r\n
disable-legacy = \"off\"\r\n disable-modern = false\r\n
ioeventfd = true\r\n vectors = 2 (0x2)\r\n
virtio-pci-bus-master-bug-migration = false\r\n
migrate-extra = true\r\n modern-pio-notify = false\r\n
x-disable-pcie = false\r\n page-per-vq = false\r\n
x-ignore-backend-features = false\r\n ats =
false\r\n x-ats-page-aligned = true\r\n
x-pcie-deverr-init = true\r\n x-pcie-lnkctl-init = true\r\n
x-pcie-pm-init = true\r\n
x-pcie-pm-no-soft-reset = false\r\n x-pcie-flr-init =
true\r\n aer = false\r\n addr = 03.0\r\n
romfile = \"\"\r\n romsize = 4294967295 (0xffffffff)\r\n
rombar = 1 (0x1)\r\n multifunction = false\r\n
x-pcie-lnksta-dllla = true\r\n x-pcie-extcap-init
= true\r\n failover_pair_id = \"\"\r\n
acpi-index = 0 (0x0)\r\n x-pcie-err-unc-mask = true\r\n
x-pcie-ari-nextfn-1 = false\r\n
x-max-bounce-buffer-size = 4096 (4 KiB)\r\n x-pcie-ext-tag
= false\r\n busnr = 1 (0x1)\r\n class Class
00ff, addr 01:03.0, pci id 1af4:1005 (sub 1af4:0004)\r\n
bar 0: i/o at 0x6120 [0x613f]\r\n bar 1: mem at 0x88403000
[0x88403fff]\r\n bar 4: mem at 0x800000c000
[0x800000ffff]\r\n bus: virtio-bus\r\n type
virtio-pci-bus\r\n dev: virtio-rng-device, id \"\"\r\n
max-bytes = 1024 (0x400)\r\n period = 1000
(0x3e8)\r\n indirect_desc = true\r\n
event_idx = true\r\n notify_on_empty = true\r\n
any_layout = true\r\n iommu_platform = false\r\n
packed = false\r\n queue_reset =
true\r\n in_order = false\r\n
use-started = true\r\n use-disabled-flag = true\r\n
x-disable-legacy-check = false\r\n dev: qxl-vga, id
\"\"\r\n ram_size = 67108864 (0x4000000)\r\n vram_size =
67108864 (0x4000000)\r\n revision = 5 (0x5)\r\n debug =
0 (0x0)\r\n guestdebug = 0 (0x0)\r\n cmdlog = 0
(0x0)\r\n ram_size_mb = 4294967295 (0xffffffff)\r\n
vram_size_mb = 4294967295 (0xffffffff)\r\n vram64_size_mb =
4294967295 (0xffffffff)\r\n vgamem_mb = 16 (0x10)\r\n
surfaces = 1024 (0x400)\r\n max_outputs = 0 (0x0)\r\n
xres = 0 (0x0)\r\n yres = 0 (0x0)\r\n global-vmstate =
false\r\n addr = 01.0\r\n romfile =
\"vgabios-qxl.bin\"\r\n romsize = 65536 (0x10000)\r\n
rombar = 1 (0x1)\r\n multifunction = false\r\n
x-pcie-lnksta-dllla = true\r\n x-pcie-extcap-init = true\r\n
failover_pair_id = \"\"\r\n acpi-index = 0 (0x0)\r\n
x-pcie-err-unc-mask = true\r\n x-pcie-ari-nextfn-1 = false\r\n
x-max-bounce-buffer-size = 4096 (4 KiB)\r\n
x-pcie-ext-tag = false\r\n busnr = 0 (0x0)\r\n class VGA
controller, addr 00:01.0, pci id 1b36:0100 (sub 1af4:1100)\r\n
bar 0: mem at 0x84000000 [0x87ffffff]\r\n bar 1: mem at
0x80000000 [0x83ffffff]\r\n bar 2: mem at 0x88640000
[0x88641fff]\r\n bar 3: i/o at 0x70c0 [0x70df]\r\n bar
6: mem at 0xffffffffffffffff [0xfffe]\r\n dev: ICH9-SMB, id
\"\"\r\n addr = 1f.3\r\n romfile = \"\"\r\n
romsize = 4294967295 (0xffffffff)\r\n rombar = 1 (0x1)\r\n
multifunction = true\r\n x-pcie-lnksta-dllla = true\r\n
x-pcie-extcap-init = true\r\n failover_pair_id = \"\"\r\n
acpi-index = 0 (0x0)\r\n x-pcie-err-unc-mask = true\r\n
x-pcie-ari-nextfn-1 = false\r\n x-max-bounce-buffer-size =
4096 (4 KiB)\r\n x-pcie-ext-tag = false\r\n busnr = 0
(0x0)\r\n class SMBus, addr 00:1f.3, pci id 8086:2930 (sub
1af4:1100)\r\n bar 4: i/o at 0x7000 [0x703f]\r\n bus:
i2c\r\n type i2c-bus\r\n dev: smbus-eeprom, id
\"\"\r\n address = 87 (0x57)\r\n dev:
smbus-eeprom, id \"\"\r\n address = 86 (0x56)\r\n
dev: smbus-eeprom, id \"\"\r\n address = 85 (0x55)\r\n
dev: smbus-eeprom, id \"\"\r\n address = 84 (0x54)\r\n
dev: smbus-eeprom, id \"\"\r\n address = 83
(0x53)\r\n dev: smbus-eeprom, id \"\"\r\n address
= 82 (0x52)\r\n dev: smbus-eeprom, id \"\"\r\n
address = 81 (0x51)\r\n dev: smbus-eeprom, id \"\"\r\n
address = 80 (0x50)\r\n dev: ich9-usb-uhci3, id \"\"\r\n
masterbus = \"usb-bus.0\"\r\n firstport = 4 (0x4)\r\n
bandwidth = 1280 (0x500)\r\n maxframes = 128 (0x80)\r\n
addr = 1d.2\r\n romfile = \"\"\r\n romsize = 4294967295
(0xffffffff)\r\n rombar = 1 (0x1)\r\n multifunction =
true\r\n x-pcie-lnksta-dllla = true\r\n
x-pcie-extcap-init = true\r\n failover_pair_id = \"\"\r\n
acpi-index = 0 (0x0)\r\n x-pcie-err-unc-mask = true\r\n
x-pcie-ari-nextfn-1 = false\r\n x-max-bounce-buffer-size = 4096
(4 KiB)\r\n x-pcie-ext-tag = false\r\n busnr = 0
(0x0)\r\n class USB controller, addr 00:1d.2, pci id 8086:2936
(sub 1af4:1100)\r\n bar 4: i/o at 0x7060 [0x707f]\r\n dev:
ich9-usb-uhci2, id \"\"\r\n masterbus = \"usb-bus.0\"\r\n
firstport = 2 (0x2)\r\n bandwidth = 1280 (0x500)\r\n
maxframes = 128 (0x80)\r\n addr = 1d.1\r\n romfile =
\"\"\r\n romsize = 4294967295 (0xffffffff)\r\n rombar =
1 (0x1)\r\n multifunction = true\r\n x-pcie-lnksta-dllla
= true\r\n x-pcie-extcap-init = true\r\n
failover_pair_id = \"\"\r\n acpi-index = 0 (0x0)\r\n
x-pcie-err-unc-mask = true\r\n x-pcie-ari-nextfn-1 = false\r\n
x-max-bounce-buffer-size = 4096 (4 KiB)\r\n
x-pcie-ext-tag = false\r\n busnr = 0 (0x0)\r\n class USB
controller, addr 00:1d.1, pci id 8086:2935 (sub 1af4:1100)\r\n
bar 4: i/o at 0x7080 [0x709f]\r\n dev: ich9-usb-uhci1, id
\"\"\r\n masterbus = \"usb-bus.0\"\r\n firstport = 0
(0x0)\r\n bandwidth = 1280 (0x500)\r\n maxframes = 128
(0x80)\r\n addr = 1d.0\r\n romfile = \"\"\r\n
romsize = 4294967295 (0xffffffff)\r\n rombar = 1 (0x1)\r\n
multifunction = true\r\n x-pcie-lnksta-dllla = true\r\n
x-pcie-extcap-init = true\r\n failover_pair_id = \"\"\r\n
acpi-index = 0 (0x0)\r\n x-pcie-err-unc-mask = true\r\n
x-pcie-ari-nextfn-1 = false\r\n x-max-bounce-buffer-size =
4096 (4 KiB)\r\n x-pcie-ext-tag = false\r\n busnr = 0
(0x0)\r\n class USB controller, addr 00:1d.0, pci id 8086:2934
(sub 1af4:1100)\r\n bar 4: i/o at 0x70a0 [0x70bf]\r\n dev:
ich9-usb-ehci1, id \"\"\r\n maxframes = 128 (0x80)\r\n
addr = 1d.7\r\n romfile = \"\"\r\n romsize = 4294967295
(0xffffffff)\r\n rombar = 1 (0x1)\r\n multifunction =
true\r\n x-pcie-lnksta-dllla = true\r\n
x-pcie-extcap-init = true\r\n failover_pair_id = \"\"\r\n
acpi-index = 0 (0x0)\r\n x-pcie-err-unc-mask = true\r\n
x-pcie-ari-nextfn-1 = false\r\n x-max-bounce-buffer-size = 4096
(4 KiB)\r\n x-pcie-ext-tag = false\r\n busnr = 0
(0x0)\r\n class USB controller, addr 00:1d.7, pci id 8086:293a
(sub 1af4:1100)\r\n bar 0: mem at 0x88643000 [0x88643fff]\r\n
bus: usb-bus.0\r\n type usb-bus\r\n dev:
usb-tablet, id \"input0\"\r\n usb_version = 2 (0x2)\r\n
display = \"\"\r\n head = 0 (0x0)\r\n
port = \"\"\r\n serial = \"\"\r\n msos-desc =
true\r\n pcap = \"\"\r\n addr 0.0, port 1, speed
480, name QEMU USB Tablet, attached\r\n dev: ich9-ahci, id
\"\"\r\n addr = 1f.2\r\n romfile = \"\"\r\n
romsize = 4294967295 (0xffffffff)\r\n rombar = 1 (0x1)\r\n
multifunction = true\r\n x-pcie-lnksta-dllla = true\r\n
x-pcie-extcap-init = true\r\n failover_pair_id = \"\"\r\n
acpi-index = 0 (0x0)\r\n x-pcie-err-unc-mask = true\r\n
x-pcie-ari-nextfn-1 = false\r\n x-max-bounce-buffer-size =
4096 (4 KiB)\r\n x-pcie-ext-tag = false\r\n busnr = 0
(0x0)\r\n class SATA controller, addr 00:1f.2, pci id 8086:2922
(sub 1af4:1100)\r\n bar 4: i/o at 0x7040 [0x705f]\r\n
bar 5: mem at 0x88642000 [0x88642fff]\r\n bus: ide.5\r\n
type IDE\r\n bus: ide.4\r\n type IDE\r\n bus:
ide.3\r\n type IDE\r\n bus: ide.2\r\n type
IDE\r\n bus: ide.1\r\n type IDE\r\n bus:
ide.0\r\n type IDE\r\n dev: ICH9-LPC, id \"\"\r\n
gpio-out \"gsi\" 24\r\n noreboot = false\r\n smm-compat
= false\r\n smm-enabled = true\r\n x-smi-broadcast =
true\r\n x-smi-cpu-hotplug = true\r\n
x-smi-cpu-hotunplug = true\r\n x-smi-swsmi-timer = false\r\n
x-smi-periodic-timer = false\r\n addr = 1f.0\r\n
romfile = \"\"\r\n romsize = 4294967295 (0xffffffff)\r\n
rombar = 1 (0x1)\r\n multifunction = true\r\n
x-pcie-lnksta-dllla = true\r\n x-pcie-extcap-init = true\r\n
failover_pair_id = \"\"\r\n acpi-index = 0 (0x0)\r\n
x-pcie-err-unc-mask = true\r\n x-pcie-ari-nextfn-1 = false\r\n
x-max-bounce-buffer-size = 4096 (4 KiB)\r\n
x-pcie-ext-tag = false\r\n busnr = 0 (0x0)\r\n class ISA
bridge, addr 00:1f.0, pci id 8086:2918 (sub 1af4:1100)\r\n bus:
isa.0\r\n type ISA\r\n dev: isa-serial, id
\"serial0\"\r\n index = 0 (0x0)\r\n iobase =
1016 (0x3f8)\r\n irq = 4 (0x4)\r\n dev: pvpanic,
id \"\"\r\n ioport = 1285 (0x505)\r\n events = 7
(0x7)\r\n dev: port92, id \"\"\r\n gpio-out
\"a20\" 1\r\n dev: vmmouse, id \"\"\r\n dev: vmport,
id \"\"\r\n x-read-set-eax = true\r\n
x-signal-unsupported-cmd = true\r\n x-report-vmx-type =
true\r\n x-cmds-v2 = true\r\n vmware-vmx-version
= 6 (0x6)\r\n vmware-vmx-type = 2 (0x2)\r\n dev:
i8042, id \"\"\r\n gpio-in \"ps2-mouse-input-irq\" 1\r\n
gpio-in \"ps2-kbd-input-irq\" 1\r\n gpio-out \"\"
2\r\n gpio-out \"a20\" 1\r\n extended-state =
true\r\n kbd-throttle = false\r\n kbd-irq = 1
(0x1)\r\n mouse-irq = 12 (0xc)\r\n dev: isa-pcspk,
id \"\"\r\n audiodev = \"\"\r\n iobase = 97
(0x61)\r\n migrate = true\r\n dev: isa-pit, id
\"\"\r\n gpio-in \"\" 1\r\n gpio-out \"\" 1\r\n
iobase = 64 (0x40)\r\n dev: isa-i8259, id \"\"\r\n
gpio-in \"\" 8\r\n gpio-out \"\" 1\r\n
iobase = 160 (0xa0)\r\n elcr_addr = 1233 (0x4d1)\r\n
elcr_mask = 222 (0xde)\r\n master = false\r\n
dev: isa-i8259, id \"\"\r\n gpio-in \"\" 8\r\n
gpio-out \"\" 1\r\n iobase = 32 (0x20)\r\n
elcr_addr = 1232 (0x4d0)\r\n elcr_mask = 248 (0xf8)\r\n
master = true\r\n dev: mc146818rtc, id \"\"\r\n
gpio-out \"\" 1\r\n base_year = 0 (0x0)\r\n
iobase = 112 (0x70)\r\n irq = 8 (0x8)\r\n
lost_tick_policy = \"discard\"\r\n dev: i8257, id \"\"\r\n
base = 192 (0xc0)\r\n page-base = 136 (0x88)\r\n
pageh-base = -1 (0xffffffffffffffff)\r\n dshift = 1
(0x1)\r\n dev: i8257, id \"\"\r\n base = 0
(0x0)\r\n page-base = 128 (0x80)\r\n pageh-base
= -1 (0xffffffffffffffff)\r\n dshift = 0 (0x0)\r\n
dev: mch, id \"\"\r\n extended-tseg-mbytes = 16 (0x10)\r\n
smbase-smram = true\r\n addr = 00.0\r\n romfile =
\"\"\r\n romsize = 4294967295 (0xffffffff)\r\n rombar =
1 (0x1)\r\n multifunction = false\r\n
x-pcie-lnksta-dllla = true\r\n x-pcie-extcap-init = true\r\n
failover_pair_id = \"\"\r\n acpi-index = 0 (0x0)\r\n
x-pcie-err-unc-mask = true\r\n x-pcie-ari-nextfn-1 = false\r\n
x-max-bounce-buffer-size = 4096 (4 KiB)\r\n
x-pcie-ext-tag = false\r\n busnr = 0 (0x0)\r\n class
Host bridge, addr 00:00.0, pci id 8086:29c0 (sub 1af4:1100)\r\n dev:
fw_cfg_io, id \"\"\r\n dma_enabled = true\r\n x-file-slots = 32
(0x20)\r\n acpi-mr-restore = true\r\n dev: kvmclock, id \"\"\r\n
x-mach-use-reliable-get-clock = true\r\n dev: kvmvapic, id
\"\"\r\n"}
> 2) whether the migration with if you disabled those features explicitly in
> 9.2.4
Could you tell me, how to disable these features?
I tried this change on both source and target qemu, but still see the
same error, althrough info virtio-status no longer report these
features.
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -3984,11 +3984,11 @@ static Property virtio_net_properties[] = {
DEFINE_PROP_STRING("duplex", VirtIONet, net_conf.duplex_str),
DEFINE_PROP_BOOL("failover", VirtIONet, failover, false),
DEFINE_PROP_BIT64("guest_uso4", VirtIONet, host_features,
- VIRTIO_NET_F_GUEST_USO4, true),
+ VIRTIO_NET_F_GUEST_USO4, false),
DEFINE_PROP_BIT64("guest_uso6", VirtIONet, host_features,
- VIRTIO_NET_F_GUEST_USO6, true),
+ VIRTIO_NET_F_GUEST_USO6, false),
DEFINE_PROP_BIT64("host_uso", VirtIONet, host_features,
- VIRTIO_NET_F_HOST_USO, true),
+ VIRTIO_NET_F_HOST_USO, false),
DEFINE_PROP_END_OF_LIST(),
};
>
> > Or should QEMU handle such feature mismatches more gracefully (e.g.,
> > automatically disable unsupported virtio features during migration)?
>
> This would break guests as it could be noticed by guests.
understood.
>
> >
> > Any guidance on how to make migration between these versions work
> > would be appreciated.
> >
> > ________________________________
> >
> > Thanks,
> > Jinpu Wang @ IONOS Cloud
> >
>
> Thanks
>
